Composite filament having reduced stickiness

ABSTRACT

COMPOSITE FILAMENTS HAVING LATENT CRIMPABILITY AND REDUCED STICKINESS WHICH CONSISTS ESSENTIALLY OF (1) A HOMOPOLYAMIDE DERIVED FROM POLYAMIDE FORMING COMPOUNDS SELECTED FROM THE GROUP CONSISTING OF LACTAMS, OMEGA-AMINOCARBOXYLIC ACIDS AND SALTS OF DIAMINES AND DICARBOXYLIC ACIDS, AND (2) A COPOLYAMIDE DERIVED FROM ONE OF SAID POLYAMIDE FORMING COMPOUNDS AND AT LEAST ONE SAID POLYAMIDE FORMING COMPOUNDS DIFFERENT THEREFROM, SAID COPOLYLAMIDE CONTAINING FROM ABOUT 0.3 TO ABOUT 3% BY WEIGHT OF A MONO- OR DIMETAL SALT OF A MONO- OR DICARBOXYLIC ACIDS, SAID HOMOPOLYAMIDE AND COPOLYAMIDE COMPONENTS BEING ECCENTRICALLY DISPOSED RELATIVE TO EACH OTHER THROUGHOUT THE LENGTH OF THE FILAMENT.

April 6, 1971 SATOSHI ANDO ETAL 3,574,047

COMPOSITE FILAMENT HAVING REDUCED STICKINESS Original Filed Dec. 14..1966

Fig.

- Time (minute) Unwinding resistance (9) O 5 IO V I5 Time (minute) Fig.2

5 go I I I l I I I I I I I I T I I INVENT()R$ 39mm: fiNDO yum/n4. 'mA mmATV JRHI- VS United States Patent 3,574,047 COMPOSITE FILAMENT HAVINGREDUCED STICKINESS Satoshi Audio and Yusaku Tanaka, Osaka, MinoruKojima,

Osaka-fir, and Kyoichi Fujimura, Ibaraki, Japan, assignors toKanegafuchi Boseki Kabushiki Kaisha, Tokyo, Japan, and Snia ViscosaSocieta Nazionale Industria Applicazioni Viscosa S.p.A., Milan, ItalyOriginal application Dec. 14, 1966, Ser. No. 601,757, now Patent No.3,554,980, dated Jan. 12, 1971. Divided and this application Sept. 3,1968, Ser. No. 798,208 Claims priority, application Japan, Dec. 23,1965, 40/79,726 Int. Cl. D01d /28; D02g 1/00 US. Cl. 161173 1 ClaimABSTRACT OF THE DISCLOSURE Composite filaments having latentcrimpability and reduced stickiness which consists essentially of (1) ahomopolyamide derived from polyamide forming compounds selected from thegroup consisting of lactams, omega-aminocarboxylic acids and salts ofdiamines and dicarboxylic acids, and (2) a copolyamide derived from oneof said polyamide forming compounds and at least one said polyamideforming compounds different therefrom, said copolyamide containing fromabout 0.3 to about 3% by weight of a monoor dimetal salt of a monoordicarboxylic acids, said homopolyamide and copolyamide components beingeccentrically disposed relative to each other throughout the length ofthe filament.

This application is a division of our copending application, Ser. No.601,757, filed Dec. 14, 1966.

The present invention relates to a method for preventing stickiness offibres produced from copolyamides.

The polyamide fibres have been heretofore used in a wide field owing toits excellent properties, but most of these fibres have been formed fromhomopolyamide's.

On the other hand, however, the homopolyamides have a number ofdisadvantages in dyeability, hygroscopicity, elastic recovering propertyetc. so that a large number of copolyamides copolymerized with at leasttwo polyamide forming materials have been proposed in order to improvethese disadvantages. It is considered that, in general, the fibresconsisting of these copolyamides have excellent properties indyeability, hygroscopicity, elastic recovering property etc. as comparedwith homopolyamide fibres and also the shrinking property in hot wateris increased, so that they suit for particular uses. A largedisadvantage to retard practice of the copolyamide fibres consists in aninherent stickness of the copolyamides, so that in spite of that saidfibres have a large number of advantages, these fibres have heretoforenot been produced commercially.

Namely, when the copolyamides are melt spun and then treated with an oilcomposition, such as, an aqueous emulsion and thereafter taken up on abobbin, the fibres stick With each other, so that when said fibres aresubjected to next processes, such as, drawing and the other processes anuneveness occurs in yarn tension when unwinding yarn from a bobbin and auniform treatment cannot be effected and moreover in the worst case, theyarn is broken and the operatability is highly damaged.

Moreover, when a side-by-side type of composite filament having a latentcrimpability, in which two or more polymers have been arranged highlyeccentrically in the cross-section of a unitary filament has beenheretofore produced, it has been necessary to use polymers havingsimilar chemical configuration and property in order to 3,574,047Patented Apr. 6, 1971 prevent separation of each component of thepolymers after spinning, so that in general, copolyamide has been usedin combination with a homopolyamide. In order to make the crystalstructures of the both polymers in these fibres different as far aspossible and to increase the difference of shrinking property, that is,to increase the latent crimpability, although it is preferable toincrease a copolymerization ratio of the copolyamide, the stickinessphenomena are remarkably increased as the copolymerization ratioincreases, so that the copolymerization ratio must be limited fairly,and therefore, it has been difficult to prepare a side-by-side type ofpolyamide composite fibres having a satisfactory crimp developability.

The inventors have made various invetsigations in order to solve theabove described problems resulting in accomplishment of the presentinvention.

The object of the present invention is to provide fibre consisting ofcopolyamide, which has no stickiness without deteriorating the otherexcellent properties.

A further object is to provide a method of producing a practical fibrefrom polyamide having such a high copolymerization ratio that apractical fibre can not be obtained as such due to a high stickness.

The other object is to provide polyamide composite filaments having nostickiness but an excellent latent crimpability, which consist of acopolyamide and a homopolyamide.

The objects above described can be attained by previously mixinghomogeneously a small quantity of metal salts of aliphatic mono ordicarboxylic acid to the copolyamide when melt spinning saidcopolyamide.

The copolyamides to be applied to the method of the present inventioninclude polyamides obtained by copoly condensating two or more polyamideforming compounds selected from the group consisting of lactams,w-aminO- carboxylic acids and salts of diamines and dicarboxylic acids,for example, the polyamide forming materials such as, 'y-butyrolactam,fi-valerolactam, e-caprolactam, heptolactam, 6-aminocaproic acid,7-aminoheptanoic acid, 9- aminononanoic acid, ll-aminoundecanoic acid orsalts of diamines, such as, tetramethylenediamine, pentamethylenediaminehexamethylenediamine, heptamethylenediamine', octamethylenediamine,nonamethylenediamine, decamethylenediamine, undecamethylenediamine,dodecamethylenediamine, metaxylylenediamine, paraxylylenediamine,bis(y-aminopropyl)ether N,N'-bis(w-aminopropyl) piperazine,l,l1-diaminoundecanone-6 and dicarboxylic acids, such as, terephthalicacid, isophthalic acid, glutaric acid, adipic acid, pimelic acid,suberic acid, azelac acid, sebacie acid, dodecandicarboxylic acid,hexahydrotereph- .thalic acid, diphenylene-4,4-dicarboxylic acid,diphenylmethane-4,4-dicarboxylic acid, diphenylether 4,4-dicarboxylicacid, diphenylpropane-4,4-dicarboxylic acid, or salts of diamines anddiearboxylic acid derivatives or salts of diamine derivatives anddicarboxylic acids.

Furthermore, these copolyamides involve polyamide copolymers added withinorganic or organic substances of delustrants, pigments, dyestuffs,light stabilizers, heat resistants, antistatic agents and plasticizers.

The metal salts of aliphatic monoand di-carboxylic acid which may beused for the method according to the invention are aliphatic carboxylicsalts in granular form of metals selected from the group consisting oflighium, beryllium, sodium, magnesium, aluminium, potassium, calcium,manganese, nickel, copper, zinc, silver, barium, mercury, thallium,lead, etc. and an aliphatic carboxylic acid forming the salts thereof ismonoand dicarboxylic acid having three or more carbon atoms.

The monocarboxylic acid includes, for example, saturated aliphatic acidssuch as propionic acid, butylic acid, valeric acid, caproic acid,enanthylic acid, caprylic acid,

pelargonic acid, capric acid, undecylic acid, laulic acid, tridecylicacid, myristic acid, pentadecylic acid, palrnitic acid, heptadecylicacid, stearic acid, nonadecanoic acid, arachic acid, behenic acid,lignoceric acid, cerotic acid, heptacosanoic acid, montanoic acid,nonacosanoic acid, melissylic acid, hentriacontanoic acid,dotriacontanoic acid, tetratriacontanoic acid, ceroplastic acid,hexatriacontanoic acid, octatriacontanoic acid, hexatetracontanoic acid,etc., and unsaturated aliphatic acids such as undecylenic acid, oleicacid, elaidic acid, cetoleic acid, erricic acid, brassidic acid, sorbicacid, linoleic acid, linolenic acid, arachidonic acid, stearolic acid,etc., whilst dicarboxylic acid includes, saturated dicarboxylic acid,such as malonic acid, succinic acid, glutaric acid,

adipic acid, pimelic acid, suberic acid, azelaic acid, etc. andunsaturated dicarboxylic acids such as maleic acid, fumaric acid, etc.

An application of metal salts of carboxylic acid having less than twocarbon atoms to the method according to the invention is not suitablebecause when said metal salts are mixed to copolyamide before and duringthe polymerization, said metal salts are disintegrated and act as achain reaction inhibitor and moreover, when said metal salts aredeposited to the fine flake or granules of copolyamide and supplied to amelting device, they are also disintegrated to very decrease a stabilityof the melt viscosity of copolyamide and deteriorate quality of fibres.As for the metal salts of aromatic monoand dicarboxylic acids other thanthose of aliphatic monoor dicarboxylic acid, not only some of them actas to vary the viscosity of copolyamide, but also in general thedispersibility thereof in the copolyamide melts is insufiicient, so thatthey are ineffective to prevent a stickiness between fibres ofcopolyamide and therefore not suitable to be used in the methodaccording to the invention.

One or more than two of these metal salts of aliphatic carboxylic acidalone or more than two of them are added into starting materials of thecopolyamide to effect the polycondensation thereof or these metal saltsare added during or after the polycondensation reaction and mixed Withagitation, whereby they are very homogeneously dispersed. Thecopolyamide containing the metal salts of aliphatic carboxylic acid in ahomogeneous dispersed state is melt spun in a conventional processdirectly or after moulded into fine granules or fine flakes.Furthermore, to fine granules or fine flakes of the copolyamide freefrom metal salts of aliphatic carboxylic acid, are deposited or mixedpowders of the metal salts and then the mass is melt spun and the metalsalts of aliphatic carboxylic acid are incorporated homogeneously intothe spun filament, whereby satisfactory results can be obtained.

In any case, it is essential that the metal salts incorporated in thecopolyamide in molten state are to be homogeneously dispersed in thecopolyamide and it is Well effected by a mechanical or physical mixingand dispersing operations such as stirring, shaking, etc., whenrequired. The aforesaid operations may be attained by a screw or a pumphoused in a melt extruder.

The content amount of the metal salts to perform the purpose of theinvention is preferable within range from 0.03 to 3% by weight basedupon the total weight of the copolyamide. [In the case of less than0.03% by weight, the effect for preventing stickiness is insufficientwhereas in the case of more than 3% by weight, yarn breakage isdeveloped during the manufacture of fibre and the drawing step andtherefore the quality of the fibre is deteriorated.

The greater the fine granule size of metal salts of aliphatic monoanddicarboxylic acid to be used in the method according to the invention,the less the dispersibility in the molten polymer will be resulting inunhomogeneous dispersion of the metal salts, so that the effectsubjected by the invention is not exhibited sufficiently and 4furthermore the breakage and unevenness of the yarn are developed duringthe spinning operation, hence it is desired to use fine granules havingparticle size of less than 50/! The mechanism of the sticking phenomenabetween the fibres of copolyamide have been hardly made clear,notwithstanding it may be presumed that the moisture contained in theoil composition contribute to the stickiness since a remarkable stickingphenomena are appeared when an aqueous emulsion is imparted to the spunfilament.

It is therefore assumed that the metal salts of aliphatic carboxylicacid contained in the copolyamide according to the method of theinvention disturb the mutual action between the fibre and waterresulting in having an ability to prevent the stickiness, although thedetailed mechanism and function thereof are not yet clear.

According to the addition of the metal salts of aliphatic monoordicarboxylic acid the stickiness of the copolyamide may be neverdeveloped and moreover the copolymerization ratio which has heretoforebeen considerably restricted owing to the increase of the stickiness isrelatively increased, whereby the polyamide fibre free from stickinesswhile having an extremely high heat shrinking property can be obtained.Furthermore, within the above range of the content an amount of themetal salts, the strength, elongation, dyeability, hygroscopicity,elastic recovering property and the other desired properties are notsubstantially decreased.

Moreover, composite filaments obtained by melting copolyamide containingmetal salts of aliphatic carboxylic acid according to the invention andwell known homopolyamide separately and by spinning them from the sameorifice simultaneously have a good mutually bonding property of the bothpolymers and also the copolymer does not show any stickiness, the latentcrimpability is increased use to the high heat shrinking property andthe fibre having extremely excellent crimpability and bulky can beobtained by heat treatment.

The fibre consisting of the copolyamide melt spun according to themethod of the invention can be treated uniformly and easily in atreatment with an oil composi tion, taking up, drawing after spinningand the succeeding knitting and weaving processes without accompanyingany disadvantage, such as, bad unwinding from a bobbin or stickinessbetween fibres as in a conventional homopolyamide fibre and furthermorethe treatment velocity can be further increased.

Furthermore, the fibres obtained by the method of the invention areprovided with the excellent properties as described above which havenever been seen in conventional homopolyamide fibres, so that they arepreferable as raw material for producing various clothings, interiordecorations, commercial articles, etc. by using solely or in combinationwith the other fibres. Particularly, if said fibres are mix-spun ormix-woven with the other fibres and then subjected to heat treatment byutilizing the high shrinking property, interesting fancy yarns or fancyfabrics can be manufactured.

For a better understanding of the invention reference is made to theaccompanying drawings:

FIG. 1 is a graph showing a resistance of a well known and drawncopolyamide yarn in unwinding it from a bobbin; and

FIG. 2 is a graph showing a resistance of the undrawn copolyamide yarnimproved by the method according to the invention in unwinding it from abobbin.

The invention will be explained further in detail by the followingexamples, in which parts and means parts by weight and by weight unlessany special reference provided.

EXAMPLE 1 To e-caprolactam was added 10% by weight of salt ofN,N-bis(w-aminopropyl)piperazine with adipic acid, mol of acetic acid asa viscosity regulator and further 0.5% by weight of calcium stearate andthe resulting mixture was heated with agitation in the nitrogen gasatmosphere at 250 C. for 7 hours under a normal pressure to conductcopolycondensation, whereafter the reacted product was extruded frombottom of a reactor in the form of strip to permit passing through waterbath so as to be cooled and solidified, which was then cut intocpolyamide fine granules of 3 mm. x 3 mm. The thusly obtained finegranules were washed with hot water of approximately 80 C. to removemonomer therefrom and dried by a vacuum drier at 80 C. under 0.1 mm. Hgto reduce the water content to 0.065% and whereafter sup plied to a heatgrid type of melt-spinning device. After residence for 40 minutes, thecopolymer melted at 270 C. was extruded from nozzles and applied withthe spinning oil composition consisting of an aqueous emulsion by meansof the rotary roller and then taken up on a bobbin as an undrawn yarnhaving 412 d./ 28 filaments.

Moreover, the polymerization and the spinning were carried out under thesame condition as the above, except that calcium stearate was not added,to produce an undrawn yarn consisting of copolyamide of the same denierfilaments which was adapted as a control yarn. In any case, thereperceived no yarn breakage and the other barriers on spinning.

The resulting two yarns were determined with respect to stickinessdegree by the following means. That is, a bobbin was arranged at rightangle to the bottom thereof. A tension meter (TI-80 type made by ToyoSokki Co.) was located at a position right above the bobbin andseparated from it 90 cm. along the extension line of the bobbin axis.

A guide was secured to a point separated 12 cm. from the tension meteralong a line inclined by 20 from the bobbin axis. A winding machine wasarranged at a position located horizontally with respect to the guide.

In the thus arranged apparatus, the yarn unwound from the bobbin waspassed through the tension meter and taken up by the winder through theguide. The unwinding resistance of the yarn perceived on the tensionmeter was recorded on a chart by means of a pen writing recorder(WTR-211 type made by Watanabe Sokki Co.). In the determined conditions,the take-up velocity was 100 m./min. and the graduation of 1 cm. in thechart to record the unwinding resistance of yarn was adjusted so as tocorrespond to a resistance of 5 g. load.

The results obtained by determining the resistances of the abovedescribed two filaments from bobbin are shown in FIGS. 1 and 2,respectively.

FIG. 1 is a diagrammatical view of a control yarn containing no calciumstearate, which shows a stickiness corresponding to to 12 g.

On the other hand FIG. 2 illustrates a resistance of the sample used inthe method according to the invention which exhibits the resistance ofonly 2 to 3 g. Moreover, these two yarns taken up on the bobbins weredrawn four times their original length and as the results the controlyarn was developed with the yarn breakage simultaneously with startingthe drawing machine, so that the drawing could not be performed. On thecontrary, the yarn containing calcium stearate was normally drawnwithout developing any yarn breakage.

EXAMPLE 2 To e-caprolactam were added 15% by weight of salt ofmetaxylylenediamine and adipic acid and mol of ethylenediamine as aviscosity regulator and the resulting mixture was heated with agitationin the nitrogen gas atmosphere at 260 C. for initial 2 hours and furtherretained for 5 hours to effect the polycondensation. The resultant masswas extruded through nozzles provided at the bottom of a reactor intothe fine granule of 2 mm. x 2 mm. which was then washed off with warmwater at 80 C. to remove the monomer therefrom, and were then dried in avacuum drier under 0.1 mm. Hg. These polyamide fine granules with watercontent of 0.061% by weight were filled into a cubic type rotary mixerwhich was in turn added with 0.3% by weight of fine particle ofaluminium palmitate having particle size of approximately 10p. and thenthe mixer was sealed and then revolved and mixed at a rate of therotation of three revolutions per minute for 3 hours, whereaftersupplied to a melt spinning apparatus to spin the yarn having 160 d./ 7filaments.

The copolyamide fine granule which was not applied with aluminiumpalmitate, was treated in the same manner as described above to take upundrawn yarn having the same denier on a bobbin, which was a controlyarn.

Moreover the stickiness degree of the samples was measured by the methodaccording to Example 1, and as the result the control yarn showed anunwinding resistance of 8 to 9 g. whereas the sample containingaluminium palmitate recorded to resistance of only 1 to 2 g. When thesesamples were further cold drawn four times their original length, as forthe control yarn the drawing operation at a high speed became impossibleowing to the high stickiness of the control yarn, so that the windingrate was reduced to 50 m./min. to continue the cold drawings.Furthermore, comparative tests of the samples of the both 40- d./ 7filaments were made with respect to the yarn properties such asdyeability, hygroscopicity, shrinkability, elastic recoveringproperties, etc. and the both yarns exhibited the same value and noinfluence due to an application of aluminium palmitate was perceived.

EXAMPLE 3 To the salt of undecamethylenediamine and terephthalic acidwere added 20% by weight of salt of paraxylylenediamine and adipic acid,0.3% by weight of titanium oxide, V mol of hexamethylenediamine basedupon the total amount of the starting material of the polycondensationas a viscosity regulator and further 1% by weight of zinc cerotate. Theresulting mixture was heated at 295 C. under an inert gas andpolymerized with agitation for 6 hours and then processed into the fineparticles of 3 mm. x 3 mm., washed with water and dried by theconventional process.

The resulting fine particles were fed into a melt extruder (YE4NT typemanufactured by Yamakawa Tekko Seisakusho) to spin denier monofilamentand furthermore the fine granules free from zinc cerotate were preparedand spun under the exactly same condition.

The resulting two 80 denier filaments were determined in respect of eachstickiness degree according to the method as mentioned in Example 1 andas the result, the control yarn free from zinc cerotate suffered thefrequent yarn breakages during the determination owing to its highstickiness degree resulting in rendering the determination impossible,while the yarn containing zinc cerotate exhibited an unwindingresistance of only 2 to 3 g.

EXAMPLE 4 To the salt of hexamethylenediamine and isophthalic acid wereadded 8% by weight of salt of paraxylylenediamine anddodecandicarboxylic and mol of acetic acid as a viscosity regulator,0.3% by weight of titanium oxide and further 0.8% by weight of zinclaurate and the resulting mixture was heated to 260 C. in the presenceof an inert gas, stirred for 7 hours to effect the polymerization,processed into the fine granules of 3 mm. x 3 mm. in the conventionalprocess, washed with water, dried and then fed into the melt process,washed with water dried and then fed into the melt spinning apparatus tospin the yarn of 280 d./4 filaments which was finally taken up on abobbin and employed as the sample for determining the stickiness.

Moreover, the copolyamide fine granules free from zinc laurate wereprepared and spun under the exactly same condition.

The resulting two yarns were determined in respect of each stickinessdegree according to the method as mentioned in Example 1 and as theresult the control yarn free from zinc laurate showed the unwindingresistance of 6 to 8 g., while the yarn containing zinc laurateexhibited the unwinding resistance of only 1 to 2 g. and a remarkableeffect of preventing the stickiness due to an application of zinclaurate was perceived. Furthermore, these two yarns were determined inrespect of an amount of spinning oil composition deposited there to bythe ether extraction process and as the result, both yarns showed thesame amount.

EXAMPLE 5 To e-caprolactam, where added 10% by Weight of salt of bis('-aminopropyl)ether and terephthalic acid, mol of acetic acid as aviscosity regulator and further 0.5% by weight of calcium adipate andthe resulting mixture was heated to 250 C. in the presence of an inertgas, stirred for 7 hours to effect the polymeriaztion and processed intothe copolyamide fine granules of 3 mm.4 x 3 mm. Moreover, thecopolyamide fine granules free from calcium adipate were prepared underthe same condition.

Furthermore, to e-caprolactam was added 5% by weight of aminocaproicacid and mol of acetic acid and the resulting mixture was polymerized at250 C. for 7 hours in the presence of an inert gas to form polycapramidefine granules of 3 mm. x 3 mm. The resulting fine granules were washedwith Water and dried, whereafter the polycapramide fine granules andcopolymeric fine granlues were fed into the melt spinning apparatus forproducing composite filaments to from two side-by-side type compositefilaments having 60 d./monofilament with the conjugating ratio of 1:1.

The thusly obtained two filaments where determined in respect of eachstickiness according to the method as mentioned in Example 1 and as theresult, the filament free from calcium adipate showed the unwindingresistance of 2 to 3 g., while the filament containing calcium adipateexhibited that of only 0.5 to 1 g. Furthermore, the two samples weresubjected to the drawing process in which the filaments free fromcalcium adipate suffered the frequent breakages owing to its highstickiness. The resultant two drawn filaments were determinedcomparatively in respect of the yarn properties and crimpability, but nosubstantial difference was perceived.

EXAMPLE 6 To E-ca'prolactam were added 12% by weight of salt consistingof hexamethylenediamine and isophthalic acid and mol of acetic acid as aviscosity regulator, which was further added or not added with 1% byweight of beryllium propionate, 1% by Weight of barium undecylenate, 1%by weight of zinc melissate, 1% by weight of magnesium sebacate and 1%by weight of calcium fumarate. The resulting six starting materials ofpolymerization were heated respectively to 250 C. in the presence of aninert gas, stirred to 7 hours to effect polymerization, processed intocopolyamide fine granules of 2 mm. x 2 mm., washed with water and driedin the conventional process. The thusly obtained fine granules were fedinto a melt spinning apparatus to form the yarn having 268 d./ 18filaments.

The resulting six bobbin filaments were determined in respect ofrespective stickiness according to the method as mentioned in Example 1and as the result, the sample filament free from metal salt suffered theyarn breakage simultaneous with the starting of a winding devicearranged in a measuring apparatus owing to its violet stickiness,resulting in rendering the determination impossible.

On the contrary, the sample containing beryllium propionate exhibitedthe unwinding resistance of 2 to 3 g., that containing bariumundecylenate showed 2 to 3 g., that containing zinc melissate showed 1to 2 g., that containing magnesium sebacate showed 3 to 4 g. and thatcontaining calcium fumarate recorded the unwinding resistance of 1 to 2g.

Furthermore, five sample filaments free from metal salt but having highstickiness were subjected to the cold drawing process for 3.8 times andthe drawing operations were all finished without developing any yarnbreakage.

What we claim is:

1. A composite filament having latent crirnpability and reducedstickiness which consists essentially of 1) a homopolyamide derived frompolyamide forming compounds selected from the group consisting oflactams, omega-aminocarboxylic acids and salts of diamines anddicarboxylic acids, and (2) a copolyamide derived from one of saidpolyamide forming compounds and at least one other of said polyamideforming compounds different therefrom, said copolyamide containing fromabout 0.3 to about 3% by weight of a monoor di-crnetal salt of a monoordicarboxylic acids, said homopolyamide and copolyamide components beingeccentrically disposed relative to each other throughout the length ofthe filament.

References Cited UNITED STATES PATENTS 2,345,700 4/1944 Dreyfus 260-783,260,689 7/ 1966 Kibler et a1 260-22 3,399,108 8/1968 Olson 16 1-175X3,418,199 12/1968 Anton et al 161-l77X ROBERT F. BURNETT, PrimaryExaminer R. L. MAY, Assistant Examiner US. Cl. X.R.

